Vibration suspension system

Abstract

A bi-directional spring member is mounted to a support platform, the bi-directional spring member being coupled to a payload. The bi-directional spring member includes a non-linear spring component having a rigid member enclosing at least a portion of a compliant planar member and a linear spring component. The compliant planar member flexes in a direction opposite a direction of low amplitude vibrational forces acting on the compliant planar member to reduce vibrational forces acting on the support platform and the linear spring member flexes to reduce high amplitude vibrational forces acting on the support platform.

The invention claimed is: 
     
       1. A vibration suppression suspension system, comprising:
 a base; 
 a platform suspended relative to the base and supported by a plurality of bi-directional spring struts, wherein each of the bi-directional spring struts comprises: 
 a non-linear spring having a spring rate that increases symmetrically in each of compression and tension as a function of displacement of the non-linear spring, the non-linear spring comprising at least one compliant planar member having a center portion; and 
 a linear spring coupled in series with the non-linear spring at the center portion of the at least one compliant planar member, wherein a longitudinal central axis of the linear spring passes through the center portion of the non-linear spring. 
 
     
     
       2. The system of  claim 1 , wherein, for a first total spring displacement, the non-linear spring comprises a spring rate that is lower than a spring rate of the linear spring, and wherein, for a second total spring displacement that is greater than the first total spring displacement, the spring rate of the non-linear spring is higher than the spring rate of the linear spring. 
     
     
       3. The system of  claim 1 , wherein the linear spring is coupled at the center portion of the at least one compliant planar member by at least one constraint member coupled to the center portion. 
     
     
       4. The system of  claim 1 , wherein the at least one compliant planar member comprises a first thickness, and is coupled to a first rigid annular member of the non-linear spring, the first rigid annular member having a second thickness, wherein the first thickness is less than the second thickness. 
     
     
       5. The system of  claim 4 , wherein the non-linear spring further comprises a second rigid annular member, wherein the at least one compliant planar member is disposed between the first and second rigid annular members. 
     
     
       6. The system of  claim 1 , wherein the at least one compliant planar member of the non-linear spring comprises a plurality of compliant planar members, each having a center portion, wherein the linear spring is coupled at the center portions of the plurality of compliant planar members. 
     
     
       7. The system of  claim 1 , wherein the at least one compliant planar member is not in direct contact with the linear spring. 
     
     
       8. The system of  claim 4 , wherein the thickness of the compliant planar member decreases in a direction away from a center of the compliant planar member. 
     
     
       9. The system of  claim 8 , wherein the thickness of the compliant planar member decreases at a linear rate or at a non-linear rate. 
     
     
       10. The system of  claim 1 , wherein the non-linear spring further comprises first and second constraint members disposed on opposing sides of the center portion of the at least one compliant planar member, the linear spring being coupled directly to at least one of the first and second constraint members. 
     
     
       11. The system of  claim 10 , wherein the non-linear spring further comprises third and fourth rigid annular members, wherein the at least one compliant planar member comprises first, second, and third compliant planar members each coupled between adjacent first, second, third, and fourth rigid annular members. 
     
     
       12. The system of  claim 11 , wherein the non-linear spring further comprise a plurality of constraint members, wherein the first, second, and third, compliant planar members are each disposed between adjacent constraint members of the plurality of constraint members. 
     
     
       13. The system of  claim 1 , wherein the non-linear spring comprises a plurality of rectangular members coupled on top of one another, wherein the non-linear spring comprises an inner thin member constrained by an outer thick member. 
     
     
       14. A system for minimizing and isolating vibration, comprising:
 a plurality of six bi-directional spring struts mounted to a support platform about a vehicle, wherein each of the spring struts comprises: 
 a non-linear spring having a non-linear spring rate that increases symmetrically each of compression and tension as a function of displacement of the non-linear spring, the non-linear spring comprising at least one compliant planar member having a center portion; and 
 a linear spring coupled in series with the non-linear spring at the center portion of the at least one compliant planar member, wherein a longitudinal central axis of the linear spring passes through the center portion of the non-linear spring; 
 wherein the plurality of spring struts is configured to attenuate vibration relative to the support platform in six degrees of freedom. 
 
     
     
       15. The system of  claim 14 , wherein the non-linear spring comprises a plurality of compliant planar members, a plurality of rigid annular members, and a plurality of constraint members, wherein each compliant planar member is coupled between adjacent rigid annular members and between adjacent constraint members, wherein each compliant planar member comprises a center portion, wherein adjacent constraint members are coupled to respective center portions of the plurality of compliant planar members. 
     
     
       16. The system of  claim 14 , wherein a longitudinal center axis of the non-linear spring is parallel with a direction of a force acting on the linear spring. 
     
     
       17. The system of  claim 14 , wherein a longitudinal center axis of the non-linear spring is not parallel to a direction of a force acting on the linear spring. 
     
     
       18. The system of  claim 14 , further comprising a platform carrying a payload, said platform being coupled to and supported by the plurality of bi-directional spring struts. 
     
     
       19. The system of  claim 14 , wherein the linear spring is selected from the group comprising a helical spring, a double helical spring, a leaf spring, or machine slotted spring. 
     
     
       20. The system of  claim 14 , wherein for a first total spring displacement, the non-linear spring comprises a spring rate that is lower than a spring rate of the linear spring, and wherein, for a second total spring displacement that is greater than the first total spring displacement, the spring rate of the non-linear spring is higher than the spring rate of the linear spring. 
     
     
       21. The system of  claim 20 , wherein the spring rate of the linear spring, and the spring rate of the non-linear spring, are equal during a predetermined distance of total spring displacement. 
     
     
       22. The system of  claim 14 , wherein a spring rate of the linear spring increases symmetrically in compression or tension as a function of displacement of the linear spring.